1. Field of the Invention
The present invention relates to a liquid ejection head and a manufacturing method of the liquid ejection head.
2. Description of the Related Art
There is known a configuration of a liquid ejection head including a recording element substrate having an ejection opening group that ejects liquid represented by ink and an energy generating element facing each ejection opening. The liquid ejection head also includes a contact part that receives an electric signal and electric power to be used for driving the energy generating element from a recording apparatus body. The connection between the contact part and the recording element substrate typically uses an electric wiring member having flexibility.
A support member and a recording element substrate forming the liquid ejection head are joined by applying an adhesive to the support member and then aligning the position of the recording element substrate. The electric wiring member and the recording element substrate are electrically connected with each other by an inner lead provided at the electric wiring member and a connection terminal provided at the recording element substrate. An electric connection part between the inner lead and the connection terminal is covered with and protected by a sealant. Since this sealant has to quickly fill a narrow portion such as a gap of the electric connection part, a sealant with relatively low viscosity is typically used.
It is desirable that the sealant that covers the electric connection part does not contact a side surface of the recording element substrate as possible. One of the reasons is that the sealant may be expanded or shrunk due to a change in environment or other factor, and may apply an external force to the recording element substrate. In recent years, with the demand for downsizing a liquid ejection head, the distances among a plurality of ink supply openings provided at the recording element substrate, and the distance from the ink supply openings to an end of the recording element substrate are decreased. When an external force is applied from the sealant to such a recording element substrate, the recording element substrate may be deformed.
Owing to this, a technology to address the above-described problem is disclosed in Japanese Patent Laid-Open No. 2012-143896. Japanese Patent Laid-Open No. 2012-142896 discloses a liquid ejection head including a recording element substrate and a support member having a recess that houses this recording element substrate. The liquid ejection head has a projection at an inner side surface of the recess. The projection causes the distance to the recording element substrate to be partly decreased. When the recording element substrate is bonded to the support member, a wall is formed with the adhesive pressed by the recording element substrate and projects, between the recording element substrate and the projection. With this wall, extension of the sealant is restricted, and the sealant hardly contacts the recording element substrate.
In the liquid ejection head described in Japanese Patent Laid-Open No. 2012-143896, since the entire bottom surface of the recess is formed of a flat surface, the adhesive pressed by the recording element substrate extends to not only the wall formation portion (between the projection and the recording element substrate) but also the entire bottom surface of the recess isotropically. Hence, to ensure the height of the wall by a certain degree to restrict the extension of the sealant, the adhesive is required by a large amount. Also, since a region near the recording element substrate (projection) is partly provided within the recess, the applied adhesive may start to flow out from the region to the inner side surface of the recess, and the height (thickness) of the adhesive required for bonding the recording element substrate may not be ensured.
In recent years, in the liquid ejection head, the array of energy generating elements arranged on the recording element substrate tends to be elongated in order to increase the recording speed. Accordingly, if the recording element substrate is elongated, the bonding area between the recording element substrate and the support member is increased, and the adhesive is required by a larger amount.